<if condition="$is_following">
    <button type="button" class="btn btn-default"  data-role="unfollow" data-follow-who="{$follow_who}" >
        已关注
    </button>
    <else/>
    <button type="button" class="btn btn-primary" data-role="follow" data-follow-who="{$follow_who}">
        关注
    </button>
</if>